The cylinder tube is processed by rolling. Because the surface layer has residual surface compressive stress, it helps to close the micro-cracks on the surface and hinder the expansion of erosion. Thereby improving the corrosion resistance of the surface, and can delay the occurrence or expansion of fatigue cracks, thus improving the fatigue strength of the cylinder tube. Through roll forming, a cold-work hardened layer is formed on the rolled surface, which reduces the elastic and plastic deformation of the contact surface of the grinding pair, thereby improving the wear resistance of the inner wall of the cylinder tube and avoiding burns caused by grinding. After rolling, the surface roughness value decreases, which can improve the matching properties.
Rolling processing is a kind of chipless processing, which uses the plastic deformation of the metal at normal temperature to smooth the microscopic unevenness of the workpiece surface to achieve the purpose of changing the surface structure, mechanical characteristics, shape and size. Therefore, this method can achieve both finishing and strengthening at the same time, which cannot be achieved by grinding.
No matter what processing method is used, there will always be fine uneven marks on the surface of the part, and there will be staggered peaks and valleys.